Designed to protect domestic industry and agriculture – although sometimes criticised for driving up the cost of consumer goods – import tariffs on goods arriving in Britain are currently dictated by Brussels as part of the UK’s membership of the EU customs union.

Leaving the EU gives the government an opportunity to set an independent trade policy and to cut the tariffs charged on imports, which Brexit backers have said would make the UK more competitive and benefit consumers.

However, the IFS said the removal of these tariffs would reduce prices by as much as 1.2% overall. That would fail to offset the 2% increase in consumer prices caused by the sudden drop in the value of the pound after the Brexit vote, which has put pressure on household budgets and led to a slowdown in spending on the high street.

The report is likely to reignite debate over the shape of Britain’s post-Brexit trade policy. Labour has called on the government to stay in a customs union with the EU, while the international trade secretary, Liam Fox, and other Brexit supporters want to strike new deals with the rest of the world.

Prof Patrick Minford, who leads the pro-Brexit Economists for Free Trade group of academics, criticised the findings of the IFS report, which was funded by the group UK in a Changing Europe. He said abolishing import tariffs could lower consumer prices by 8% and boost economic output.